Media-centric companies are often interested in tracking the number of times that audience members are exposed to various media compositions (e.g., television programs, motion pictures, internet videos, radio programs, etc.). In some instance, to track such exposures, companies generate audio and/or video signatures of media compositions (e.g., a representation of some, preferably unique, portion of the media composition or the signal used to transport the media composition) that can be used to determine when those media compositions are presented to audience members. The media compositions may be identified by comparing the signature to a database of reference signatures. Additionally or alternatively, companies transmit identification codes (e.g., watermarks) with media compositions to monitor presentations of those media compositions to audience members by comparing identification codes retrieved from media compositions presented to audience members with reference identification codes stored in a reference database. Like the reference signature, the reference codes are stored in association with information descriptive of the corresponding media compositions to enable identification of the media compositions.
Media ratings and metering information are typically generated by collecting media exposure information from a group of statistically selected households. Each of the statistically selected households typically has a data logging and processing unit such as, for example, a stationary or portable media measurement device, commonly referred to as a “metering device” or “meter.” The meter typically includes sensors to gather data from the monitored media presentation devices (e.g., audio-video (AV) devices) at the selected site and deliver the gathered data to a centralized location for processing.